Systems And Methods For Uplink Control Information Signaling Design

ABSTRACT

According to certain embodiments, a method by a wireless device is provided for transmitting uplink control information (UCI) on a serving cell on the unlicensed spectrum. The method includes formatting the UCI as a shortened control signalling transmission and transmitting the UCI formatted as the shortened control signalling transmission to a network node. The shortened control signalling transmission is transmitted during a transmission opportunity on the serving cell on the unlicensed spectrum without performing channel sensing.

PRIORITY

This application claims priority to U.S. Patent Provisional ApplicationNo. 62/134,276 filed on Mar. 17, 2015, entitled “Methods of UCI Designin LAA,” the disclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates, in general, to wireless communicationsand, more particularly, systems and methods for systems and methods foruplink control information (UCI) signaling design for operation on theunlicensed spectrum.

BACKGROUND

The 3GPP Rel-13 feature “Licensed-Assisted Access” (LAA) allows LTEequipment to also operate in the unlicensed 5 GHz radio spectrum. Theunlicensed 5 GHz spectrum is used as a complement to the licensedspectrum. Accordingly, devices (i.e., LTE user equipment (UEs)) connectin the licensed spectrum (primary cell or PCell) and use carrieraggregation to benefit from additional transmission capacity in theunlicensed spectrum (secondary cell or SCell). To reduce the changesrequired for aggregating licensed and unlicensed spectrum, the LTE frametiming in the primary cell is simultaneously used in the secondary cell.

Regulatory requirements, however, may not permit transmissions in theunlicensed spectrum without prior channel sensing. Since the unlicensedspectrum must be shared with other radios of similar or dissimilarwireless technologies, a so-called listen-before-talk (LBT) method needsto be applied. LBT involves sensing the medium for a pre-defined minimumamount of time and backing off if the channel is busy. Today, theunlicensed 5 GHz spectrum is mainly used by equipment implementing theIEEE 802.11 Wireless Local Area Network (WLAN) standard, also knownunder its marketing brand as “Wi-Fi.”

In Europe, the LBT procedure is under the scope of EN 301.893regulation. For LAA to operate in the 5 GHz spectrum the LAA LBTprocedure shall conform to requirements and minimum behaviors set forthin EN 301.893. However, additional system designs and steps are neededto ensure coexistence of Wi-Fi and LAA with EN 301.893 LBT procedures.

As an example, U.S. Pat. No. 8,774,209 B2, “Apparatus and method forspectrum sharing using listen-before-talk with quiet periods,” discusseswhere LBT is adopted by frame-based OFDM systems to determine whetherthe channel is free prior to transmission. A maximum transmissionduration timer is used to limit the duration of a transmission burst,and is followed by a quiet period. In contrast, this invention focusesonly on the LBT phase of a load-based OFDM system, and is designed toensure fairer coexistence with other radio access technologies such asWi-Fi while also satisfying EN 301.893 regulations.

Long Term Evolution (LTE)

FIG. 1 illustrates the basic LTE downlink physical resource. LTE usesOrthogonal Frequency Division Multiplexing (OFDM) in the downlink andDiscrete Fourier Transform (DFT)-spread OFDM (also referred to assingle-carrier FDMA (SC-FDMA)) in the uplink. The basic LTE downlinkphysical resource can thus be seen as a time-frequency grid, where eachresource element corresponds to one OFDM subcarrier during one OFDMsymbol interval. The uplink subframe has the same subcarrier spacing asthe downlink, and the same number of SC-FDMA symbols in the time domainas OFDM symbols in the downlink.

FIG. 2 illustrates the LTE time-domain structure. In the time domain,LTE downlink transmissions are organized into radio frames of 10 ms,each radio frame 210 consisting of ten equally-sized subframes of lengthT_(subframe)=1 ms, in the illustrated example embodiment. Each subframecomprises two slots of duration 0.5 ms each, and the slot numberingwithin a frame ranges from 0 to 19. For normal cyclic prefix, onesubframe consists of 14 OFDM symbols. The duration of each symbol isapproximately 71.4 μs.

Furthermore, the resource allocation in LTE is typically described interms of resource blocks (RBs), where a RB corresponds to one slot (0.5ms) in the time domain and 12 contiguous subcarriers in the frequencydomain. A pair of two adjacent RBs in time direction (1.0 ms) is knownas a resource block pair. RBs are numbered in the frequency domain,starting with 0 from one end of the system bandwidth.

Downlink transmissions are dynamically scheduled. For example, in eachsubframe, the base station transmits control information about whichterminals data is transmitted to and upon which resource blocks the datais transmitted, in the current downlink subframe. This control signalingis typically transmitted in the first 1, 2, 3, or 4 OFDM symbols in eachsubframe and the number n=1, 2, 3, or 4 is known as the Control FormatIndicator (CFI). The downlink subframe also contains common referencesymbols, which are known to the receiver and used for coherentdemodulation of e.g., the control information. FIG. 3 illustrates anexample downlink subframe with CFI=3 OFDM symbols as control. Thereference symbols shown there are the cell specific reference symbols(CRS) and are used to support multiple functions including fine time andfrequency synchronization and channel estimation for certaintransmission modes.

From LTE Rel-11 onwards, DL or UL resource assignments can also bescheduled on the enhanced Physical Downlink Control Channel (EPDCCH). Bycontrast, according to Rel-8 to Rel-10, only the Physical DownlinkControl Channel (PDCCH) is available.

Physical Downlink Control Channel and Enhanced Physical Downlink ControlChannel

The Physical Downlink Control Channel (PDCCH) and the Enhanced PhysicalDownlink Control Channel (EPDCCH) may be used to carry downlink controlinformation (DCI) such as scheduling decisions and power-controlcommands. For example, DCI may include downlink scheduling assignments,including Physical Downlink Shared Channel (PDCCH) resource indication,transport format, hybrid-Automatic Repeat Request (HARQ) information,and/or control information related to spatial multiplexing whereapplicable. A downlink scheduling assignment may also include a commandfor power control of the PUCCH used for transmission of HARQacknowledgements in response to downlink scheduling assignments.Additionally or alternatively, DCI may include uplink scheduling grants,including Physical Uplink Shared Channel (PUSCH) resource indication,transport format, and HARQ-related information. An uplink schedulinggrant may also include a command for power control of the PUSCH.Additionally or alternatively, DCI may include power-control commandsfor a set of terminals as a complement to the commands included in thescheduling assignments/grants.

One PDCCH/EPDCCH may carry one DCI message containing one of the groupsof information listed above. As multiple terminals can be scheduledsimultaneously, and each terminal can be scheduled on both downlink anduplink simultaneously, there must be a possibility to transmit multiplescheduling messages within each subframe. Each scheduling message may betransmitted on separate PDCCH/EPDCCH resources, and consequently thereare typically multiple simultaneous PDCCH/EPDCCH transmissions withineach subframe in each cell. Furthermore, to support differentradio-channel conditions, link adaptation can be used, where the coderate of the PDCCH/EPDCCH is selected by adapting the resource usage forthe PDCCH/EPDCCH, to match the radio-channel conditions.

In LTE, the UL transmission scheduling command is transmitted from theeNB to the UE. There is a fixed delay between the time the schedulingcommand is transmitted and the time the UE transmits the UL signalspecified in the standard. This delay is provisioned to allow the UEtime to decode the PDCCH/EPDCCH and prepare the UL signal fortransmission. For a FDD serving cell, this UL grant delay is 4 ms. For aTDD serving cell, this UL grant can be greater than 4 ms.

Carrier Aggregation

The LTE Rel-10 standard supports bandwidths larger than 20 MHz. Oneimportant requirement on LTE Rel-10 is to assure backward compatibilitywith LTE Rel-8. This should also include spectrum compatibility. Thatwould imply that an LTE Rel-10 carrier, wider than 20 MHz, should appearas a number of LTE carriers to an LTE Rel-8 terminal. Each such carriercan be referred to as a Component Carrier (CC). In particular for earlyLTE Rel-10 deployments it can be expected that there will be a smallernumber of LTE Rel-10-capable terminals compared to many LTE legacyterminals. Therefore, it is necessary to assure an efficient use of awide carrier also for legacy terminals, i.e. that it is possible toimplement carriers where legacy terminals can be scheduled in all partsof the wideband LTE Rel-10 carrier. The straightforward way to obtainthis would be by means of carrier aggregation.

FIG. 4 illustrates aggregated bandwidth by carrier aggregation (CA). CAimplies that an LTE Rel-10 terminal can receive multiple CC, where theCC have, or at least the possibility to have, the same structure as aRel-8 carrier. A CA-capable UE is assigned a primary cell (PCell) whichis always activated, and one or more secondary cells (SCells) which maybe activated or deactivated dynamically.

The number of aggregated CC as well as the bandwidth of the individualCC may be different for uplink and downlink. A symmetric configurationrefers to the case where the number of CCs in downlink and uplink is thesame whereas an asymmetric configuration refers to the case that thenumber of CCs is different. It is important to note that the number ofCCs configured in a cell may be different from the number of CCs seen bya terminal. For example, a terminal may support more downlink CCs thanuplink CCs, even though the cell is configured with the same number ofuplink and downlink CCs.

In addition, a key feature of carrier aggregation in the ability toperform cross-carrier scheduling. This mechanism allows an EPDCCH on oneCC to schedule data transmissions on another CC by means of a 3-bitCarrier Indicator Field (CIF) inserted at the beginning of the EPDCCHmessages. For data transmissions on a given CC, a wireless device mayexpect to receive scheduling messages on the EPDCCH on just oneCC—either the same CC, or a different CC via cross-carrier scheduling.The mapping from EPDCCH to PDSCH is also configured semi-statically.

LTE Scheduling Methods

In LTE, the scheduling information of DL and UL transmission on thePCell is transmitted on the PCell using PDCCH or EPDCCH. This basicscheduling mechanism is referred to as the self-scheduling method inLTE. For a SCell, two scheduling mechanisms are supported: SCellself-scheduling and SCell cross-carrier scheduling. According to SCellself-scheduling, the scheduling information of DL and UL transmission onthe SCell is transmitted on the same SCell itself using PDCCH or EPDCCH.By contrast, according to SCell cross-carrier scheduling, the networkcan also configure a SCell via higher layer signaling. In this approach,the scheduling information of DL and UL transmission on a SCell istransmitted on a second cell using PDCCH or EPDCCH. The second cell maybe the PCell or another SCell.

For LTE, the DL and UL scheduling approaches are configured together.Thus, the DL and UL transmissions of a cell are either bothself-scheduling or both cross-carrier scheduling.

Wireless Local Area Network

In typical deployments of WLAN, carrier sense multiple access withcollision avoidance (CSMA/CA) is used for medium access. This means thatthe channel is sensed to perform a clear channel assessment (CCA), and atransmission is initiated only if the channel is declared as Idle. Incase the channel is declared as Busy, the transmission is essentiallydeferred until the channel is deemed to be Idle.

When the range of several access points (APs) using the same frequencyoverlap, all transmissions related to one AP might be deferred in case atransmission on the same frequency to or from another AP within rangecan be detected. Effectively, this means that if several APs are withinrange, they will have to share the channel in time, and the throughputfor the individual APs may be severely degraded. FIG. 5 illustrates anexample listen before talk (LBT) mechanism on a single unlicensedchannel.

In the single-channel LBT case, after a Wi-Fi station A transmits a dataframe to a station B, station B shall transmit the ACK frame back tostation A with a delay of 16 μs. Such an ACK frame is transmitted bystation B without performing a LBT operation. To prevent another stationinterfering with such an ACK frame transmission, a station shall deferfor a duration of 34 μs (referred to as Distributed CoordinationFunction Inter-frame Spacing, or DCF Inter-frame Spacing, or DIFS) afterthe channel is observed to be occupied before assessing again whetherthe channel is occupied.

Therefore, a station that wishes to transmit first performs a CCA bysensing the medium for a fixed duration DIFS. If the medium is idle thenthe station assumes that it may take ownership of the medium and begin aframe exchange sequence. If the medium is busy, the station waits forthe medium to go idle, defers for DIFS, and waits for a further randombackoff period.

To further prevent a station from occupying the channel continuously andthereby prevent other stations from accessing the channel, it isrequired for a station wishing to transmit again after a transmission iscompleted to perform a random backoff.

The Point Coordination Function Inter-frame Spacing, or PCF Inter-frameSpacing, or PIFS, is used to gain priority access to the medium, and isshorter than the DIFS duration. Among other cases, it can be used bystations (STAs) operating under PCF, to transmit Beacon Frames withpriority. At the nominal beginning of each Contention-Free Period (CFP),the PC shall sense the medium. When the medium is determined to be idlefor one PIFS period (generally 25 μs), the PC shall transmit a Beaconframe containing the CF Parameter Set element and a delivery trafficindication message element.

Load-Based Clear Channel Assessment

For a device not utilizing the Wi-Fi protocol, Europe Regulation EN301.893, v. 1.7.1 provides the certain requirements and minimum behaviorfor the load-based clear channel assessment. FIG. 6 illustrates anexample LBT mechanism in conformance with EN 301.893. The requirementsand minimum behavior are as follows:

-   -   1. Before a transmission or a burst of transmissions on an        operating channel, the equipment shall perform a CCA check by        detecting the energy level of the operating channel. The        equipment shall observe the operating channel(s) for the        duration of the CCA observation time, which is set by the        manufacturer and shall be not less than 20 μs. The Operating        Channel shall be considered occupied if the energy level in the        channel exceeds the threshold corresponding to the power level        given in enumerated point #5 below. If the equipment finds the        channel to be clear, it may send transmissions immediately (see        point #3 below).    -   2. If during CCA check, the equipment finds an Operating Channel        occupied, it shall not transmit in that channel. The equipment        shall perform an Extended CCA check in which the Operating        Channel is observed for the duration of a random factor N        multiplied by the CCA observation time. N defines the number of        clear idle slots resulting in a total Idle Period that needs to        be observed before initiation of the transmission. The value of        N shall be randomly selected in the range 1 . . . q every time        an Extended CCA (eCCA) is required and the value stored in a        counter. The value of q is selected by the manufacturer in the        range 4 . . . 32. This selected value shall be declared by the        manufacturer (see clause 5.3.1 q)). The counter is decremented        every time a CCA slot is considered to be “unoccupied”. When the        counter reaches zero, the equipment may transmit.    -    It should be noted that the equipment is allowed to continue        Short Control Signaling Transmissions on this channel providing        it complies with the requirements in clause 4.9.2.3.    -    For equipment having simultaneous transmissions on multiple        (adjacent or non-adjacent) operating channels, the equipment is        allowed to continue transmissions on other operating channels        providing the CCA check did not detect any signals on those        channels.    -   3. The total time that an equipment makes use of an operating        channel is the maximum channel occupancy time which shall be        less than (13/32)×q ms, with q as defined in point #2 above.        After the maximum channel occupancy time, the device shall        perform the extended CCA described in point #2 above.    -   4. Upon correct reception of a packet which was intended for the        equipment, the equipment may skip CCA and immediately proceed        with the transmission of management and control frames (e.g. ACK        and Block ACK frames). A consecutive sequence of transmissions        by the equipment, without it performing a new CCA, shall not        exceed the maximum channel occupancy time as defined in point #3        above.    -    For the purpose of multi-cast, the ACK transmissions        (associated with the same data packet) of the individual devices        are allowed to take place in a sequence.    -   5. The energy detection threshold for the CCA shall be        proportional to the maximum transmit power (PH) of the        transmitter: for a 23 dBm e.i.r.p. transmitter the CCA threshold        level (TL) shall be equal or lower than −73 dBm/MHz at the input        to the receiver (assuming a 0 dBi receive antenna). For other        transmit power levels, the CCA threshold level TL shall be        calculated using the formula: TL=−73 dBm/MHz+23−PH (assuming a 0        dBi receive antenna and PH specified in dBm e.i.r.p.).

Licensed-Assisted Access (LAA) to Unlicensed Spectrum Using LTE

Up to now, the spectrum used by LTE has been dedicated to LTE. This hasthe advantage that the LTE system does not need to care about thecoexistence issue and the spectrum efficiency can be maximized. However,the spectrum allocated to LTE is limited, and the allocated spectrumcannot meet the ever increasing demand for larger throughput fromapplications and/or services. Therefore, a new work item has beeninitiated in 3GPP on extending LTE to exploit unlicensed spectrum inaddition to licensed spectrum.

FIG. 7 illustrates licensed-assisted access (LAA) to unlicensed spectrumusing LTE carrier aggregation. As depicted, a wireless device isconnected to a primary cell (PCell) in the licensed band and one or moresecondary cells (SCells) in the unlicensed band. Herein, a secondarycell in unlicensed spectrum may be referred to as a LAA secondary cell(LAA SCell). The LAA SCell may operate in downlink only mode or operatewith both UL and DL traffic. Furthermore, certain embodiments mayinclude LTE nodes operating in standalone mode in license-exemptchannels without assistance from a licensed cell. Unlicensed spectrumcan, by definition, be simultaneously used by multiple differenttechnologies. Therefore, LTE needs to consider the coexistence issuewith other systems such as IEEE 802.11 (Wi-Fi).

For LAA, the backoff counter does not have to be decremented when a slotis sensed to be idle during the ECCA procedure. Additionally, anysubframe can be used for either DL or UL transmission.

To coexist fairly with the Wi-Fi system, transmission on the SCell mustconform to LBT protocols in order to avoid collisions and causinginterference to on-going transmissions. This includes both performingLBT before commencing transmissions, and limiting the maximum durationof a single transmission burst. The maximum transmission burst durationis specified by country and region-specific relations, e.g., 4 ms inJapan and 13 ms according to EN 301.893.

FIG. 8 illustrates LAA to the unlicensed spectrum with LBT and UL and DLtransmissions within a transmission opportunity (TXOP). Specifically, inthe example depicted, a 4 ms LAA TXOP after successful LBT consists of aDL transmission burst with two subframes followed by an UL transmissionburst of two subframes. Thus, there is TXOP sharing between the downlinkand the uplink. The UL burst may perform a single CCA, a short extendedCCA, or no CCA before transmission.

UL Transmission in LAA

There may be two possible approaches to support UL transmission on anLAA SCell. In the first approach, the UE follows an LBT protocol toattempt channel access after receiving the UL transmission schedulingcommand. FIG. 9 illustrates UL LAA transmissions based on an UL LBTprotocol. In the depicted example, the system has a 4 ms channeloccupancy time. Thus, the LBT protocol is designed to allow 4 ms DLchannel occupancy time and 4 ms UL channel occupancy time.

According to a second approach, the UE does not follow any LBT protocolto initiate channel access after receiving the UL transmissionscheduling command. FIG. 10 illustrates UL LAA transmissions based on areverse direction grant (RDG) protocol. In the depicted example, thesystem has an 8 ms channel occupancy time. Thus, the LBT protocol isdesigned to allow 8 ms total channel occupancy time between DL and ULtransmissions. LBT and CCA are performed by the eNB before the start ofDL transmissions.

Currently, there is no uplink control information (UCI) design for LTEoperation on the unlicensed spectrum.

SUMMARY

To address the foregoing problems with existing solutions, disclosed issystems and methods for uplink control information (UCI) signalingdesign for operation on the unlicensed spectrum.

According to certain embodiments, a method by a wireless device isprovided for transmitting uplink control information (UCI) on a servingcell on the unlicensed spectrum. The method includes formatting the UCIas a shortened control signalling transmission and transmitting the UCIformatted as the shortened control signalling transmission to a networknode. The shortened control signalling transmission is transmittedduring a transmission opportunity on the serving cell on the unlicensedspectrum without performing channel sensing.

According to certain embodiments, a method by a wireless device isprovided for transmitting at least one hybrid automatic repeat request(HARQ) acknowledgement on a serving cell on the unlicensed spectrum. Themethod includes determining, by the wireless device, whether thewireless device has channel access to at least one serving cell on theunlicensed spectrum on which physical uplink shared channel (PUSCH)transmission is scheduled. If the wireless device has channel access tothe at least one serving cell on which the PUSCH transmission isscheduled, the at least one HARQ acknowledgement is transmitted on theat least one serving cell multiplexed with scheduled PUSCH data.Conversely, if the wireless device does not have channel access to theat least one serving cell on which the PUSCH transmission is scheduled,the at least one HARQ acknowledgement is formatted in a shortenedphysical uplink control channel (PUCCH) transmission format, and the atleast one HARQ acknowledgement is transmitted in the shortened PUCCHtransmission format during a transmission opportunity on at least oneserving cell on the unlicensed spectrum without performing channelsensing.

According to certain embodiments, a method by a network node is providedfor configuring transmission of uplink control information (UCI) on aselected one of a plurality of cells. The method includes assigning, bythe network node, each of the plurality of cells to a selected one of aplurality of cell groups. A cell selection is transmitted to a wirelessdevice. The cell selection identifies a cell within each the pluralityof cell groups for use in transmitting the UCI.

According to certain embodiments, a method by a wireless device isprovided for transmitting uplink control information (UCI). The methodincludes performing a carrier sensing procedure. Based on the carriersensing procedure, it is determined whether the wireless device haschannel access on at least one secondary cell (SCell) on the unlicensedspectrum. If the wireless device has channel access to the at least oneSCell on the unlicensed spectrum, the UCI is transmitted on the at leastone SCell. If the wireless device does not have channel access to the atleast one SCell on the unlicensed spectrum, the UCI is scheduled to betransmitted on a cell on the licensed spectrum in a next transmission.

Certain embodiments of the present disclosure may provide one or moretechnical advantages. For example, certain embodiments may provide goodbackwards compatibility with legacy UCI mechanisms. Another advantagemay be that certain embodiments provide high reliability for UCI for alicensed carrier. Still another advantage may be that certainembodiments provide a greater probability of quick UCI feedback on anunlicensed carrier.

Other advantages may be readily apparent to one having skill in the art.Certain embodiments may have none, some, or all of the recitedadvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the disclosed embodiments and theirfeatures and advantages, reference is now made to the followingdescription, taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates the basic LTE downlink physical resource;

FIG. 2 illustrates the LTE time-domain structure;

FIG. 3 illustrates an example downlink subframe;

FIG. 4 illustrates aggregated bandwidth by carrier aggregation;

FIG. 5 illustrates an example listen before talk (LBT) mechanism on asingle unlicensed channel;

FIG. 6 illustrates another example LBT mechanism;

FIG. 7 illustrates licensed-assisted access (LAA) to unlicensed spectrumusing LTE carrier aggregation;

FIG. 8 illustrates LAA to the unlicensed spectrum with LBT and uplink(UL) and downlink (DL) transmissions within a transmission opportunity(TXOP);

FIG. 9 illustrates UL LAA transmissions based on an UL LBT protocol;

FIG. 10 illustrates UL LAA transmissions based on a reverse directiongrant protocol;

FIG. 11 illustrates an exemplary network node for uplink controlinformation (UCI) signaling design for LAA, in accordance with certainembodiments;

FIG. 12 illustrates an exemplary wireless device for transmitting UCI ona serving cell in the unlicensed spectrum, in accordance with certainembodiments;

FIG. 13 illustrates an exemplary method by a wireless device fortransmitting UCI on a serving cell in the unlicensed spectrum, inaccordance with certain embodiments;

FIG. 14 illustrates an exemplary method by a wireless device fortransmitting a hybrid automatic repeat request (HARQ) acknowledgment ona serving cell in the unlicensed spectrum, in accordance with certainembodiments;

FIG. 15 illustrates an alternative exemplary method by a wireless devicefor transmitting UCI, in accordance with certain embodiments;

FIG. 16 illustrates an exemplary computer networking virtual apparatusfor transmitting UCI on a serving cell in the unlicensed spectrum, inaccordance with certain embodiments;

FIG. 17 illustrate an example network node for configuring transmissionof UCI on a selected cell, according to certain embodiments;

FIG. 18 illustrates an example method for configuring transmission ofUCI on a selected cell, according to certain embodiments;

FIG. 19 illustrates an example cell grouping, according to certainembodiments;

FIG. 20 illustrates an alternative example cell grouping, according tocertain embodiments;

FIG. 21 illustrates an example computer networking virtual apparatus forconfiguring transmission of UCI on a selected cell, according to certainembodiments; and

FIG. 22 illustrates an exemplary radio network controller or corenetwork node, in accordance with certain embodiments.

DETAILED DESCRIPTION

FIG. 11 is a block diagram illustrating an embodiment of a network 100implementing uplink control information (UCI) signaling design for LAA,in accordance with certain embodiments. Network 100 includes one or morewireless devices 110A-C, which may be interchangeably referred to aswireless devices 110 or UEs 110, and network nodes 115A-C, which may beinterchangeably referred to as network nodes 115 or eNodeBs 115. Awireless device 110 may communicate with network nodes 115 over awireless interface. For example, wireless device 110A may transmitwireless signals to one or more of network nodes 115, and/or receivewireless signals from one or more of network nodes 115. The wirelesssignals may contain voice traffic, data traffic, control signals, and/orany other suitable information. In some embodiments, an area of wirelesssignal coverage associated with a network node 115 may be referred to asa cell. In some embodiments, wireless devices 110 may have D2Dcapability. Thus, wireless devices 110 may be able to receive signalsfrom and/or transmit signals directly to another wireless device 110.For example, wireless device 110A may be able to receive signals fromand/or transmit signals to wireless device 110B.

In certain embodiments, network nodes 115 may interface with a radionetwork controller (not depicted in FIG. 11). The radio networkcontroller may control network nodes 115 and may provide certain radioresource management functions, mobility management functions, and/orother suitable functions. In certain embodiments, the functions of theradio network controller may be included in network node 115. The radionetwork controller may interface with a core network node. In certainembodiments, the radio network controller may interface with the corenetwork node via an interconnecting network. The interconnecting networkmay refer to any interconnecting system capable of transmitting audio,video, signals, data, messages, or any combination of the preceding. Theinterconnecting network may include all or a portion of a publicswitched telephone network (PSTN), a public or private data network, alocal area network (LAN), a metropolitan area network (MAN), a wide areanetwork (WAN), a local, regional, or global communication or computernetwork such as the Internet, a wireline or wireless network, anenterprise intranet, or any other suitable communication link, includingcombinations thereof.

In some embodiments, the core network node may manage the establishmentof communication sessions and various other functionalities for wirelessdevices 110. Wireless devices 110 may exchange certain signals with thecore network node using the non-access stratum layer. In non-accessstratum signaling, signals between wireless devices 110 and the corenetwork node may be transparently passed through the radio accessnetwork. In certain embodiments, network nodes 115 may interface withone or more network nodes over an internode interface. For example,network nodes 115A and 115B may interface over an X2 interface.

As described above, example embodiments of network 100 may include oneor more wireless devices 110, and one or more different types of networknodes capable of communicating (directly or indirectly) with wirelessdevices 110. Wireless device 110 may refer to any type of wirelessdevice communicating with a node and/or with another wireless device ina cellular or mobile communication system. Examples of wireless device110 include a mobile phone, a smart phone, a PDA (Personal DigitalAssistant), a portable computer (e.g., laptop, tablet), a sensor, amodem, a machine-type-communication (MTC) device/machine-to-machine(M2M) device, laptop embedded equipment (LEE), laptop mounted equipment(LME), USB dongles, a D2D capable device, or another device that canprovide wireless communication. A wireless device 110 may also bereferred to as UE, a station (STA), a device, or a terminal in someembodiments. Also, in some embodiments, generic terminology, “radionetwork node” (or simply “network node”) is used. It can be any kind ofnetwork node, which may comprise a Node B, base station (BS),multi-standard radio (MSR) radio node such as MSR BS, eNode B, networkcontroller, radio network controller (RNC), base station controller(BSC), relay donor node controlling relay, base transceiver station(BTS), access point (AP), transmission points, transmission nodes, RRU,RRH, nodes in distributed antenna system (DAS), core network node (e.g.MSC, MME etc.), O&M, OSS, SON, positioning node (e.g. E-SMLC), MDT, orany suitable network node. Example embodiments of wireless devices 110,network nodes 115, and other network nodes (such as radio networkcontroller or core network node) are described in more detail withrespect to FIGS. 12, 17, and 22, respectively.

Although FIG. 11 illustrates a particular arrangement of network 100,the present disclosure contemplates that the various embodimentsdescribed herein may be applied to a variety of networks having anysuitable configuration. For example, network 100 may include anysuitable number of wireless devices 110 and network nodes 115, as wellas any additional elements suitable to support communication betweenwireless devices or between a wireless device and another communicationdevice (such as a landline telephone). Furthermore, although certainembodiments may be described as implemented in a long term evolution(LTE) network, the embodiments may be implemented in any appropriatetype of telecommunication system supporting any suitable communicationstandards and using any suitable components, and are applicable to anyradio access technology (RAT) or multi-RAT systems in which the wirelessdevice receives and/or transmits signals (e.g., data). For example, thevarious embodiments described herein may be applicable to LTE,LTE-Advanced, LTE-U UMTS, HSPA, GSM, cdma2000, WiMax, WiFi, anothersuitable radio access technology, or any suitable combination of one ormore radio access technologies. Although certain embodiments may bedescribed in the context of wireless transmissions in the downlink, thepresent disclosure contemplates that the various embodiments are equallyapplicable in the uplink and vice versa.

The UCI signaling techniques described herein are applicable to both LAALTE and standalone LTE operation in license-exempt channels. Thedescribed techniques are generally applicable for transmissions fromboth network nodes 115 and wireless devices 110. Likewise, thetechniques are applicable to both frequency-division duplex (FDD) andtime-division duplex (TDD) systems.

FIG. 12 illustrates an example wireless device 110 for transmitting UCIon a serving cell in the unlicensed spectrum, in accordance with certainembodiments. As depicted, wireless device 110 includes transceiver 210,processor 220, and memory 230. In some embodiments, transceiver 210facilitates transmitting wireless signals to and receiving wirelesssignals from network node 115 (e.g., via an antenna), processor 220executes instructions to provide some or all of the functionalitydescribed above as being provided by wireless device 110, and memory 230stores the instructions executed by processor 220.

Processor 220 may include any suitable combination of hardware andsoftware implemented in one or more modules to execute instructions andmanipulate data to perform some or all of the described functions ofwireless device 110. In some embodiments, processor 220 may include, forexample, one or more computers, one or more central processing units(CPUs), one or more microprocessors, one or more applications, and/orother logic.

Memory 230 is generally operable to store instructions, such as acomputer program, software, an application including one or more oflogic, rules, algorithms, code, tables, etc. and/or other instructionscapable of being executed by a processor. Examples of memory 230 includecomputer memory (for example, Random Access Memory (RAM) or Read OnlyMemory (ROM)), mass storage media (for example, a hard disk), removablestorage media (for example, a Compact Disk (CD) or a Digital Video Disk(DVD)), and/or or any other volatile or non-volatile, non-transitorycomputer-readable and/or computer-executable memory devices that storeinformation.

Other embodiments of wireless device 110 may include additionalcomponents beyond those shown in FIG. 12 that may be responsible forproviding certain aspects of the wireless device's functionality,including any of the functionality described above and/or any additionalfunctionality (including any functionality necessary to support thesolution described above).

FIG. 13 illustrates an exemplary method 300 by a wireless device 110 fortransmitting UCI on a serving cell in the unlicensed spectrum, inaccordance with certain embodiments. The method begins at step 304 whenthe UCI is formatted as a shortened control signaling transmission. Incertain embodiments, the UCI may include a HARQ acknowledgement. Incertain embodiments, the shortened control signaling transmission is ashortened physical uplink control channel (PUCCH) format. The PUCCHformat may be transmitted on N OFDM symbols, wherein 0<=N<=7.

In other embodiments, the UCI may include aperiodic control signalinginformation (CSI) and the shortened control signaling transmission maybe a shortened physical uplink shared channel (PUSCH) format. The PUSCHformat may be transmitted on N OFDM symbols, wherein 0<=N<=7.

At step 306, the UCI formatted as the shortened control signalingtransmission is transmitted to a network node 115. In certainembodiments, the shortened control signaling transmission is transmittedduring a transmission opportunity (TxOP) on the serving cell on theunlicensed spectrum without performing channel sensing prior to thetransmission. In certain embodiments, the UCI transmission follows theRDG protocol and transmitted after a DL transmission during atransmission opportunity. In certain embodiments, the duration of theshortened control signaling transmission may not exceed a maximumthreshold. For example, the maximum threshold may be approximately fivepercent of the transmission opportunity, in a particular embodiment. Incertain embodiments, the serving cell includes a license assisted accessSCell on the unlicensed spectrum. In certain embodiments, the servingcell includes a cell operating on the unlicensed spectrum withoutassistance from a licensed cell.

FIG. 14 illustrates an exemplary method by a wireless device fortransmitting a hybrid automatic repeat request (HARQ) acknowledgment ona serving cell in the unlicensed spectrum, in accordance with certainembodiments. The method begins at step 404 when it is determined whetherthe wireless device 110 has PUSCH access on at least one unlicensedserving cell. In certain embodiments, the serving cell may include alicense assisted access SCell on the unlicensed spectrum. In certainembodiments, the serving cell includes a cell operating on theunlicensed spectrum without assistance from a licensed cell.

If it is determined that the wireless device 110 has PUSCH access on theat least one unlicensed serving cell, the method continues to step 406.At step 406, a HARQ acknowledgment is transmitted on the serving cellwith multiplexed PUSCH. The method may then terminate. In a particularembodiment, the PUSCH transmission may be transmitted on a plurality ofuplink carriers, and an uplink carrier must be selected from theplurality of uplink carriers for transmitting HARQ acknowledgement. Forexample, the selected uplink carrier may be the same carrier as thePUCCH transmission is transmitted on, a carrier with a highest cellindex, a carrier with a lowest cell index, and/or a carrier on which anaperiodic CSI report is requested to be transmitted.

Returning to step 404, if it is determined instead that the wirelessdevice 110 does not have PUSCH access on the at least one unlicensedserving cell, the method continues to step 408. At step 408, the HARQacknowledgment is formatted in a shortened PUCCH transmission format.The shortened PUCCH transmission format is then transmitted, at step410, during a transmission opportunity on at least one serving cell onthe unlicensed spectrum without performing channel sensing. In certainembodiments, the UCI transmission follows the RDG protocol andtransmitted after a DL transmission during a transmission opportunity.In certain embodiments, the duration of the shortened PUCCH transmissionformat may not exceed a maximum threshold. For example, the maximumthreshold may be approximately five percent such that the shortenedPUCCH transmission format does may not exceed approximately five percentof the transmission opportunity.

FIG. 15 illustrates an alternative exemplary method 500 by a wirelessdevice 110 for transmitting UCI, in accordance with certain embodiments.The method begins at step 504 when a carrier sensing procedure isperformed. Based on the carrier sensing procedure, it is determined, atstep 506, whether the wireless device 110 has channel access on at leastone serving cell on the unlicensed spectrum. In certain embodiments, theserving cell may include a license assisted access SCell on theunlicensed spectrum. In certain embodiments, the serving cell includes acell operating on the unlicensed spectrum without assistance from alicensed cell.

If the wireless device 110 has channel access on the at least oneserving cell on the unlicensed spectrum, the method proceeds to step508, and the UCI is transmitted on the at least one serving cell on theunlicensed spectrum. Conversely, if it is determined at step 504 thatthe wireless device 110 does not have channel access on the at least oneserving cell on the unlicensed spectrum, the method proceeds to step510. At step 510, the UCI is scheduled on a cell on the licensedspectrum in the next transmission opportunity. In certain embodiments,the UCI includes aperiodic CSI. In other embodiments, the UCI mayinclude a HARQ acknowledgment.

In certain embodiments, the method for transmitting UCI on a servingcell in the unlicensed spectrum as described above may be performed by acomputer networking virtual apparatus. FIG. 16 illustrates an examplecomputer networking virtual apparatus 600 for transmitting UCI on aserving cell in the unlicensed spectrum, according to certainembodiments. In certain embodiments, computer networking virtualapparatus 600 may include modules for performing methods similar tothose illustrated and described with regard to FIGS. 13, 14, and 15. Forexample, in the depicted embodiment, computer virtual apparatus 600includes at least one performing module 610, at least one determiningmodule 620, at least one formatting module 630, at least onetransmitting module 640, at least one scheduling module 650, and anyother suitable modules for transmitting UCI on a serving cell in theunlicensed spectrum. In some embodiments, one or more of the performingmodule 610, determining module 620, formatting module 630, transmittingmodule 640, scheduling module 650, or any other suitable module may beimplemented using one or more processors 220 of FIG. 12. In certainembodiments, the functions of two or more of the various modules may becombined into a single module. Further, though the computer virtualapparatus 600 is depicted as including a module for performing each ofthe operations described above with regard to the combination of FIGS.13, 14, and 15, it is recognized that computer virtual apparatus 600 mayinclude modules for performing the operations of a selected one of themethods described above with regard to FIGS. 13, 14, and 15. Forexample, computer virtual apparatus 600 that performs the method of FIG.13 may include only formatting module 630 and transmitting module 640.

The at least one performing module 610 may perform any performingfunctions of computer networking virtual apparatus 600. For example,performing module 610 may perform a carrier sensing procedure, in aparticular embodiment.

The at least one determining module 620 may perform any determiningfunctions of computer networking virtual apparatus 600. For example, ina particular embodiment, determining module 620 may determine, based onthe carrier sensing procedure performed by performing module 610,whether a wireless device 110 has channel access on at least one servingcell on the unlicensed spectrum. In another embodiment, determiningmodule 610 may determine whether a wireless device 110 has channelaccess to at least one serving cell on the unlicensed spectrum on whicha PUSCH transmission is scheduled.

The formatting module 630 may perform any formatting functions ofcomputer networking virtual apparatus 600. For example, formattingmodule 630 may format a UCI as a shortened control signallingtransmission. In certain embodiments, the shortened control signallingtransmission may include a shortened PUCCH format. For example, a HARQacknowledgement may be formatted as a shortened PUCCH format. In otherembodiments, the shortened control signalling transmission may include ashortened PUSCH format.

The transmitting module 640 may perform the transmitting functions ofcomputer networking virtual apparatus 600. For example, transmittingmodule 640 may transmit, to a network node 115, a UCI formatted as ashortened control signalling transmission. The shortened format may betransmitted during a transmission opportunity on a serving cell on theunlicensed spectrum without performing channel sensing, in certainembodiments. In other embodiments, transmitting module 640 may transmitat least one HARQ acknowledgment multiplexed with scheduled PUSCH datawhere the wireless device 110 has channel access to the serving cell onthe unlicensed spectrum on which a PUSCH transmission is scheduled. Instill other embodiments, if the wireless device does not have channelaccess to the serving cell on which the PUSCH transmission is scheduled,transmitting module 640 may transmit a HARQ acknowledgement in theshortened PUCCH transmission format during a transmission opportunity onthe serving cell in the unlicensed spectrum without performing channelsensing. In still another embodiment, transmitting module 640 maytransmit UCI on the at least one serving cell where the wireless device110 has channel access to the at least one serving cell on theunlicensed spectrum.

The scheduling module 650 may perform the scheduling functions ofcomputer networking virtual apparatus 600. For example, schedulingmodule 650 may schedule a UCI to be transmitted on a cell on thelicensed spectrum in a next transmission where the wireless device 110does not have channel access to the at least one serving cell on theunlicensed spectrum.

Other embodiments of computer networking virtual apparatus 600 mayinclude additional components beyond those shown in FIG. 16 that may beresponsible for providing certain aspects of the wireless device's 110functionality, including any of the functionality described above and/orany additional functionality (including any functionality necessary tosupport the solutions described above). The various different types ofwireless devices 110 may include components having the same physicalhardware but configured (e.g., via programming) to support differentradio access technologies, or may represent partly or entirely differentphysical components.

FIG. 17 illustrate an example network node for configuring transmissionof UCI on a selected cell, according to certain embodiments. Asdescribed above, network node 115 may be any type of radio network nodeor any network node that communicates with a wireless device and/or withanother network node. Examples of a network node 1115 are providedabove.

Network nodes 115 may be deployed throughout network 100 as a homogenousdeployment, heterogeneous deployment, or mixed deployment. A homogeneousdeployment may generally describe a deployment made up of the same (orsimilar) type of network nodes 115 and/or similar coverage and cellsizes and inter-site distances. A heterogeneous deployment may generallydescribe deployments using a variety of types of network nodes 115having different cell sizes, transmit powers, capacities, and inter-sitedistances. For example, a heterogeneous deployment may include aplurality of low-power nodes placed throughout a macro-cell layout.Mixed deployments may include a mix of homogenous portions andheterogeneous portions.

Network node 115 may include one or more of transceiver 710, processor720, memory 730, and network interface 740. In some embodiments,transceiver 710 facilitates transmitting wireless signals to andreceiving wireless signals from wireless device 110 (e.g., via anantenna), processor 720 executes instructions to provide some or all ofthe functionality described above as being provided by a network node115, memory 730 stores the instructions executed by processor 720, andnetwork interface 740 communicates signals to backend networkcomponents, such as a gateway, switch, router, Internet, Public SwitchedTelephone Network (PSTN), core network nodes or radio networkcontrollers, etc.

In certain embodiments, network node 115 may be capable of usingmulti-antenna techniques, and may be equipped with multiple antennas andcapable of supporting MIMO techniques. The one or more antennas may havecontrollable polarization. In other words, each element may have twoco-located sub elements with different polarizations (e.g., 90 degreeseparation as in cross-polarization), so that different sets ofbeamforming weights will give the emitted wave different polarization.

Processor 720 may include any suitable combination of hardware andsoftware implemented in one or more modules to execute instructions andmanipulate data to perform some or all of the described functions ofnetwork node 115. In some embodiments, processor 720 may include, forexample, one or more computers, one or more central processing units(CPUs), one or more microprocessors, one or more applications, and/orother logic.

Memory 730 is generally operable to store instructions, such as acomputer program, software, an application including one or more oflogic, rules, algorithms, code, tables, etc. and/or other instructionscapable of being executed by a processor. Examples of memory 1130include computer memory (for example, Random Access Memory (RAM) or ReadOnly Memory (ROM)), mass storage media (for example, a hard disk),removable storage media (for example, a Compact Disk (CD) or a DigitalVideo Disk (DVD)), and/or or any other volatile or non-volatile,non-transitory computer-readable and/or computer-executable memorydevices that store information.

In some embodiments, network interface 740 is communicatively coupled toprocessor 720 and may refer to any suitable device operable to receiveinput for network node 115, send output from network node 115, performsuitable processing of the input or output or both, communicate to otherdevices, or any combination of the preceding. Network interface 740 mayinclude appropriate hardware (e.g., port, modem, network interface card,etc.) and software, including protocol conversion and data processingcapabilities, to communicate through a network.

Other embodiments of network node 115 may include additional componentsbeyond those shown in FIG. 17 that may be responsible for providingcertain aspects of the radio network node's functionality, including anyof the functionality described above and/or any additional functionality(including any functionality necessary to support the solutionsdescribed above). The various different types of network nodes mayinclude components having the same physical hardware but configured(e.g., via programming) to support different radio access technologies,or may represent partly or entirely different physical components.Additionally, the terms first and second are provided for examplepurposes only and may be interchanged.

FIG. 18 illustrates an example method 800 by network node 115 forconfiguring transmission of UCI on a selected cell, according to certainembodiments. The method begins at step 804 when each of a plurality ofcells is assigned to a selected one of a plurality of cell groups.Example cell grouping schemes are described below with regard to FIGS.19 and 20.

At step 806, a cell selection is transmitted to a wireless device 110.The cell selection may identify a cell within each of the plurality ofcell groups for use in transmitting UCI by the wireless device 110. Incertain embodiments, the UCI may include a HARQ acknowledgement. Inother embodiments, the UCI may include aperiodic CSI.

FIG. 19 illustrates an example cell grouping scheme 900 that includes afirst grouping of cells 902 and a second grouping of cells 904,according to certain embodiments. In the depicted embodiment, the cellsare grouped such that there is no cross-over between licensed carriersand unlicensed carriers within each group. Specifically, first groupingof cells 902 includes cells 906A-D on the licensed spectrum, whilesecond grouping of cells 904 includes cells 908A-D on the unlicensedspectrum. In the example embodiment, cell 906A on the licensed spectrumis designated as the PCell for cells 906A-D and 908A-D. Thus, cells906B-D and 908A-D comprise SCells on the licensed and unlicensedspectrums, respectively.

In certain embodiments, no cross-group UCI may be supported. Thus, wherethe UCI comprises HARQ feedback for licensed carrier 906A-D, the DL HARQfeedback may only be transmitted on a licensed carrier 906A-D within thecell grouping 902. Such an embodiment is backwards compatible withlegacy HARQ feedback mechanisms. Likewise, where the UCI comprisesaperiodic CSI reporting for licensed carrier 906A-D, the aperiodic CSImay only be transmitted on a licensed carrier 906A-D within the cellgrouping 902, in certain embodiments. This ensures that HARQ feedbackand/or aperiodic CSI for licensed carriers 906A-D are sent only on thelicensed carriers 906A-D and, thus, ensures the robustness and shortlatency of UCI transmission for licensed carriers.

FIG. 20 illustrates an alternative example cell grouping scheme 1000that includes a first grouping of cells 1002 and a second grouping ofcells 1004, according to certain embodiments. In the depictedembodiment, the groupings of cells 1002 and 1004 are permitted to havecells including carriers on both the licensed and unlicensed spectrum.For example, first grouping of cells 1002 has cells 1006A and 1006B onthe licensed spectrum and cells 1008A and 1008B on the unlicensedspectrum. As another example, second grouping of cells 1004 has cells1006C and 1006D on the licensed spectrum and cells 1008C and 1008D onthe unlicensed spectrum. Licensed carrier 1006A is designated as thePCell for first grouping of cells 1002 and second grouping of cells1004, and cells 1006B-D and 1008A-D are SCells.

In certain embodiments, no cross-group UCI may be supported. Becauseeach grouping on cells 1002 and 1004 includes at least cell on alicensed carrier, DL HARQ feedback and/or aperiodic CSI, in particularembodiments, may be transmitted on a licensed carrier for each group.Thus, cells 1006A-B may be used to transmit DL HARQ feedback and/oraperiodic CSI for first cell grouping 1002, while cells 1006C-D may beused to transmit DL HARQ feedback and/or aperiodic CSI for second cellgrouping 1004.

In certain embodiments, the method for configuring transmission of UCIon a selected cell as described above may be performed by a computernetworking virtual apparatus. FIG. 21 illustrates an example computernetworking virtual apparatus 1100 for configuring transmission of UCI ona selected cell, according to certain embodiments. In certainembodiments, computer networking virtual apparatus 1100 may include atleast one assigning module 1110, at least one transmitting module 1120,and any other suitable modules for configuring transmission of UCI on aselected cell. In certain embodiments, virtual computing device 1100 mayalternatively or additionally include modules for performing stepssimilar to those described above with regard to the method illustratedand described in FIG. 18. In some embodiments, one or more of themodules may be implemented using one or more processors 720 of FIG. 17.The modules may include analog and/or digital circuitry configured toperform the functions disclosed herein. In certain embodiments, thefunctions of two or more of the various modules may be combined into asingle module. Conversely, the functions of one module may, in certainembodiments, be performed by more than one module.

The at least one assigning module 1110 may perform the assigningfunctions of computer networking virtual apparatus 1100. For example,assigning module 1110 may assign cells to a selected one of a pluralityof cell groups. As described above, the cell groups may include licensedcells, unlicensed cells, or some combination of licensed and unlicensedcells.

The transmitting module 1120 may perform the transmitting functions ofcomputer networking virtual apparatus 1100. For example, transmittingmodule 1120 may a cell selection to a wireless device 110. The cellselection may identify a cell within each of the plurality of cellgroups for use in transmitting UCI. In certain embodiments, the cellselection may identify a PCell for transmission of the UCI for all cellgroupings. In other embodiments, the cell selection may identify aselected one of the plurality of secondary cells on the unlicensedspectrum for transmission of UCI for at least one grouping of cells. Instill other embodiments, the cell selection may identify an SCell on thelicensed spectrum for transmission of the UCI for at least one groupingof cells.

Other embodiments of computer networking virtual apparatus 1100 mayinclude additional components beyond those shown in FIG. 21 that may beresponsible for providing certain aspects of the radio network node's115 functionality, including any of the functionality described aboveand/or any additional functionality (including any functionalitynecessary to support the solutions described above). The variousdifferent types of network nodes 115 may include components having thesame physical hardware but configured (e.g., via programming) to supportdifferent radio access technologies, or may represent partly or entirelydifferent physical components.

FIG. 22 illustrates an exemplary radio network controller or corenetwork node 1200, in accordance with certain embodiments. Examples ofnetwork nodes such as radio network controller or core network node 1200can include a mobile switching center (MSC), a serving GPRS support node(SGSN), a mobility management entity (MME), a radio network controller(RNC), a base station controller (BSC), and so on. The radio networkcontroller or core network node 1200 may include processor 1220, memory1230, and network interface 1240. In some embodiments, processor 1220executes instructions to provide some or all of the functionalitydescribed above as being provided by the network node, memory 1230stores the instructions executed by processor 1220, and networkinterface 1240 communicates signals to any suitable node, such as agateway, switch, router, Internet, Public Switched Telephone Network(PSTN), network nodes 115, radio network controllers or core networknodes 1200, etc.

Processor 1220 may include any suitable combination of hardware andsoftware implemented in one or more modules to execute instructions andmanipulate data to perform some or all of the described functions of theradio network controller or core network node 1900. In some embodiments,processor 1220 may include, for example, one or more computers, one ormore central processing units (CPUs), one or more microprocessors, oneor more applications, and/or other logic.

Memory 1230 is generally operable to store instructions, such as acomputer program, software, an application including one or more oflogic, rules, algorithms, code, tables, etc. and/or other instructionscapable of being executed by a processor. Examples of memory 1230include computer memory (for example, Random Access Memory (RAM) or ReadOnly Memory (ROM)), mass storage media (for example, a hard disk),removable storage media (for example, a Compact Disk (CD) or a DigitalVideo Disk (DVD)), and/or or any other volatile or non-volatile,non-transitory computer-readable and/or computer-executable memorydevices that store information.

In some embodiments, network interface 1240 is communicatively coupledto processor 1220 and may refer to any suitable device operable toreceive input for the network node, send output from the network node,perform suitable processing of the input or output or both, communicateto other devices, or any combination of the preceding. Network interface1240 may include appropriate hardware (e.g., port, modem, networkinterface card, etc.) and software, including protocol conversion anddata processing capabilities, to communicate through a network.

Other embodiments of the network node may include additional componentsbeyond those shown in FIG. 12 that may be responsible for providingcertain aspects of the network node's functionality, including any ofthe functionality described above and/or any additional functionality(including any functionality necessary to support the solution describedabove).

According to certain embodiments, a method by a wireless device isprovided for transmitting uplink control information (UCI) on a servingcell on the unlicensed spectrum. The method includes formatting the UCIas a shortened control signalling transmission and transmitting the UCIformatted as the shortened control signalling transmission to a networknode. The shortened control signalling transmission is transmittedduring a transmission opportunity on the serving cell on the unlicensedspectrum without performing channel sensing.

According to certain embodiments, a method by a wireless device isprovided for transmitting at least one hybrid automatic repeat request(HARQ) acknowledgement on a serving cell on the unlicensed spectrum. Themethod includes determining, by the wireless device, whether thewireless device has channel access to at least one serving cell on theunlicensed spectrum on which physical uplink shared channel (PUSCH)transmission is scheduled. If the wireless device has channel access tothe at least one serving cell on which the PUSCH transmission isscheduled, the at least one HARQ acknowledgement is transmitted on theat least one serving cell multiplexed with scheduled PUSCH data.Conversely, if the wireless device does not have channel access to theat least one serving cell on which the PUSCH transmission is scheduled,the at least one HARQ acknowledgement is formatted in a shortenedphysical uplink control channel (PUCCH) transmission format, and the atleast one HARQ acknowledgement is transmitted in the shortened PUCCHtransmission format during a transmission opportunity on at least oneserving cell on the unlicensed spectrum without performing channelsensing.

According to certain embodiments, a method by a network node is providedfor configuring transmission of uplink control information (UCI) on aselected one of a plurality of cells. The method includes assigning, bythe network node, each of the plurality of cells to a selected one of aplurality of cell groups. A cell selection is transmitted to a wirelessdevice. The cell selection identifies a cell within each the pluralityof cell groups for use in transmitting the UCI.

According to certain embodiments, a method by a wireless device isprovided for transmitting uplink control information (UCI). The methodincludes performing a carrier sensing procedure. Based on the carriersensing procedure, it is determined whether the wireless device haschannel access on at least one secondary cell (SCell) on the unlicensedspectrum. If the wireless device has channel access to the at least oneSCell on the unlicensed spectrum, the UCI is transmitted on the at leastone SCell. If the wireless device does not have channel access to the atleast one SCell on the unlicensed spectrum, the UCI is scheduled to betransmitted on a cell on the licensed spectrum in a next transmission.

Certain embodiments of the present disclosure may provide one or moretechnical advantages. For example, certain embodiments may provide goodbackwards compatibility with legacy UCI mechanisms. Another advantagemay be that certain embodiments provide high reliability for UCI for alicensed carrier. Still another advantage may be that certainembodiments provide a greater probability of quick UCI feedback on anunlicensed carrier.

Modifications, additions, or omissions may be made to the systems andapparatuses described herein without departing from the scope of thedisclosure. The components of the systems and apparatuses may beintegrated or separated. Moreover, the operations of the systems andapparatuses may be performed by more, fewer, or other components.Additionally, operations of the systems and apparatuses may be performedusing any suitable logic comprising software, hardware, and/or otherlogic. As used in this document, “each” refers to each member of a setor each member of a subset of a set.

Modifications, additions, or omissions may be made to the methodsdescribed herein without departing from the scope of the disclosure. Themethods may include more, fewer, or other steps. Additionally, steps maybe performed in any suitable order.

Although this disclosure has been described in terms of certainembodiments, alterations and permutations of the embodiments will beapparent to those skilled in the art. Accordingly, the above descriptionof the embodiments does not constrain this disclosure. Other changes,substitutions, and alterations are possible without departing from thespirit and scope of this disclosure, as defined by the following claims.

Abbreviations used in the preceding description include:

-   CCA Clear Channel Assessment-   CW Contention Window-   DCF Distributed Coordination Function-   DIFS DCF Inter-frame Spacing-   DL Downlink-   DRS Discovery Reference Signal-   eNB evolved NodeB, base station-   LAA Licensed-Assisted Access-   LBT Listen before talk-   MRBC Multiple Random Backoff Channels-   PDCCH Physical Downlink Control Channel-   PIFS PCF Inter-frame Spacing-   PUSCH Physical Uplink Shared Channel-   QoS Quality of Service-   SCell Secondary Cell-   SRBC Single Random Backoff Channel-   SIFS Short Inter-frame Spacing-   TTI Transmission-Time Interval-   TXOP Transmission Opportunity-   UE User Equipment-   UL Uplink Control Information

1. A method by a wireless device for transmitting uplink controlinformation (UCI) on a serving cell on the unlicensed spectrum, themethod comprising: formatting, by the wireless device, the UCI as ashortened control signalling transmission; and transmitting, by thewireless device, the UCI formatted as the shortened control signallingtransmission to a network node, wherein the shortened control signallingtransmission transmitted during a transmission opportunity on theserving cell on the unlicensed spectrum without performing channelsensing
 2. The method of claim 1, wherein the UCI comprises HARQacknowledgement.
 3. The method of claim 2, wherein the shortened controlsignalling transmission is a shortened physical uplink control channel(PUCCH) format, the shortened PUCCH transmitted on N OFDM symbols,wherein 0<=N<=7.
 4. The method of claim 1, wherein a duration of theshortened control signalling transmission does not exceed a maximumthreshold.
 5. The method of claim 4, wherein the maximum threshold isfive percent of the transmission opportunity.
 6. The method of claim 1,wherein the UCI comprises aperiodic CSI.
 7. The method of claim 6,wherein the shortened control signalling transmission is a shortenedphysical uplink shared channel (PUSCH) format, the shortened PUSCHtransmitted on N OFDM symbols, wherein 0<=N<=7.
 8. The method of claim1, wherein the serving cell comprises a license assisted access SCell onthe unlicensed spectrum.
 9. A method by a wireless device fortransmitting at least one HARQ acknowledgement on a serving cell on theunlicensed spectrum, the method comprising: determining, by the wirelessdevice, whether the wireless device has channel access to at least oneserving cell on the unlicensed spectrum on which physical uplink sharedchannel (PUSCH) transmission is scheduled; if the wireless device haschannel access to the at least one serving cell on which the PUSCHtransmission is scheduled, transmitting the at least one HARQacknowledgement on the at least one serving cell multiplexed withscheduled PUSCH data; and if the wireless device does not have channelaccess to the at least one serving cell on which the PUSCH transmissionis scheduled, formatting, by the wireless device, the at least one HARQacknowledgement in a shortened physical uplink control channel (PUCCH)transmission format; and transmitting the at least one HARQacknowledgement in the shortened PUCCH transmission format during atransmission opportunity on at least one serving cell on the unlicensedspectrum without performing channel sensing.
 10. The method of claim 9,wherein a duration of the shortened PUCCH transmission format does notexceed a maximum threshold.
 11. The method of claim 10, wherein themaximum threshold is five percent of the transmission opportunity. 12.The method of claim 9, wherein the serving cell comprises a licenseassisted access SCell on the unlicensed spectrum.
 13. The method ofclaim 9, further comprising: determining that the wireless device hasaccess to the uplink carriers on which the PUSCH transmission isscheduled, wherein the PUSCH transmission is allowed to be transmittedon a plurality uplink carriers; and selecting one of the plurality ofuplink carriers for transmission of the UCI, wherein the one of theplurality of uplink carriers is selected from the group consisting of: asame carrier as the PUCCH transmission is transmitted on; a carrier witha highest cell index; a carrier with a lowest cell index; and a carrieron which an aperiodic CSI report is requested to be transmitted.
 14. Amethod by a network node for configuring transmission of uplink controlinformation (UCI) on a selected one of a plurality of cells, the methodcomprising: assigning, by the network node, each of the plurality ofcells to a selected one of a plurality of cell groups; transmitting, bythe network node, a cell selection to a wireless device, the cellselection identifying a cell within each of the plurality of cell groupsfor use in transmitting the UCI.
 15. The method of claim 14, wherein:the plurality of cell groups comprise a first cell group, the first cellgroup comprising a primary cell and a plurality of secondary cells onthe licensed spectrum; and the cell selection identifies the primarycell within the first cell group for transmission of the UCI.
 16. Themethod of claim 14, wherein: the plurality of cell groups comprise afirst cell group, the first cell group comprising a plurality ofsecondary cells on the unlicensed spectrum; the cell selectionidentifies a selected one of the plurality of secondary cells on theunlicensed spectrum for transmission of the UCI.
 17. The method of claim14, wherein the plurality of cell groups comprise: a first cell groupcomprising a primary cell on the licensed spectrum and at least onesecondary cell on the unlicensed spectrum; and the cell selectionidentifies the primary cell within the first cell group for transmissionof the UCI.
 18. The method of claim 14, wherein the plurality of cellgroups comprise: a first cell group comprising at least one secondarycell on the licensed spectrum and at least one secondary cell on theunlicensed spectrum; and the cell selection identifies a secondary cellon the licensed spectrum within the first cell group for transmission ofthe UCI.
 19. The method of claim 14, wherein the UCI comprises HARQacknowledgment.
 20. The method of claim 14, wherein the UCI comprisesaperiodic CSI.
 21. A method by a wireless device for transmitting uplinkcontrol information (UCI), the method comprising: performing, by thewireless device, a carrier sensing procedure; based on the carriersensing procedure, determine whether the wireless device has channelaccess on at least one serving cell on the unlicensed spectrum; if thewireless device has channel access to the at least one serving cell onthe unlicensed spectrum, transmitting the UCI on the at least oneserving cell; and if the wireless device does not have channel access tothe at least one serving cell on the unlicensed spectrum, scheduling theUCI to be transmitted on at least one serving cell on the licensedspectrum in a next transmission.
 22. The method of claim 21, wherein theUCI comprises aperiodic CSI.
 23. The method of claim 21, wherein the UCIcomprises a HARQ acknowledgment.
 24. The method of claim 21, wherein theat least one serving cell comprises a license assisted access SCell onthe unlicensed spectrum.